That is too many. It's more of a Java bug!!! However, LW's 4.12 has reduced the no. of threads it uses. So if you don't already have it, I'd recommend updating to the latest version,
http://www.limewire.com/english/content/download.shtml
Too many threads will increase the amount of memory & cpu it uses. AFAIK The bug refers to Java threads closing off & releasing their memory they've used up.